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Transport Bug in Exch 2010 SP3 RU1 on Win 2012 – #550 4.4.7 QUEUE.Expired

Some users are receiving bounce messages when they send email with attachment such as Winmail.dat to external recipients, but plain text is alright:

The server has tried to deliver this message, without success, and has stopped trying. Please try sending this message again. If the problem continues, contact your helpdesk.
 #550 4.4.7 QUEUE.Expired; message expired ##

Further investigation:
Step 1. Company has a mail gateway and hygiene system (mailmarshal) sitting between company email server and Internet, searched the Email in mailmarshal, but no record, which means the email did not event pass through Exchange server.

Step 2. Review the Queues under Tools in Exchange toolbox.
To duplicate the issue, resend the emial and then go to Exchange toolbox, Toolbox, Queue Viewer. Double click Submission,  You find some messages are stuck in the queues on your Exchange 2013 server, and the error reads: “A storage transient failure has occurred during content conversion”

Cause: Outlook Web App translates TNEF into MAPI and displays the formatted messages. However, other email clients that don’t understand TNEF typically display TNEF formatted messages as plain text messages with Winmail.dat or Win.dat attachments.

Extra consideration: This usually only happens to some company, and Note: this may cause the “forwarded email in plain text” issue.

Workaround: We only enable TNEF for the domain with this problem. run the following command from Exchange Management Shell:

1. Create a remote domain:

New-RemoteDomain -DomainName -Name thedomain

2. Enable the TNEF

Set-RemoteDomain -Identity thedomain -TNEFEnabled $true

3. In order to view the current setting:

get-remotedomain |fl

TNFEEnabled True

Note: TNFEEnabled is set to Null (‘blank’) by default.


after changing the TNFEEnabled setting, we don’t need to restart the Microsoft Exchange Transport Service for good measure.

additional findings:  Changing the Message Format for the Organization to ‘Determined by individual user settings’ (Organization Config -> Hub Transport -> Remote Domains -> Default -> Message Format) and then configuring the users Outlook who have the stuck messages from RTF to HTML stops their messages from getting stuck in the queue.  Note: changing the organization Message Format setting will revert the TNFEEnabled setting back to default ‘Null’ (blank).

TNFEEnabled Null default setting

TNFEENabled set to Null (blank) by default.

4. To remove the existing problem message in the queue

Get-queue | Get-message | where {$_.Subject -like "*keyword*"} | remove-message


Emails sent in HTML format are received in Plain Text format


You have composed and sent an email in HTML format. The recipient received the message in Plain Text format with none of the images or text decoration displayed.


Various causes can result in this behaviour. Commonly the issue can also occur if the Remote Domain configuration settings specified on the Microsoft Exchange server are incorrectly configured.

To view the current Remote Domain configuration, run the command:

Get-RemoteDomain | fl

If the ContentType property is specified as MimeText, this is likely to result in the undesired behaviour of the message format being converted.

The ContentType property should be configured as either MimeHtmlText or MimeHtml.
MimeHtml will enforce HTML format.
MimeHtmlText will allow the receiving email client to decide the best format to display the message.


To correctly configure the Remote Domain settings, follow the steps below:

1. On the Microsoft Exchange server, launch the Exchange Management Shell (EMS).
2. To change the ContentType propertly, run the command:

Set-RemoteDomain -Identity <name> -ContentType <type>

Note: The identify name should be populated with the name of the remote domain specified on the Microsoft Exchange Server. By default this is *.


Set-RemoteDomain -Identity * -ContentType MimeHtml